diff --git a/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/BadGatewayProblem.java b/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/BadGatewayProblem.java
index 6cb8aab8..9ebf01eb 100644
--- a/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/BadGatewayProblem.java
+++ b/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/BadGatewayProblem.java
@@ -2,6 +2,7 @@
 
 import java.net.URI;
 
+import io.github.belgif.rest.problem.api.FluentProblem;
 import io.github.belgif.rest.problem.api.ProblemType;
 import io.github.belgif.rest.problem.api.ServerProblem;
 import io.github.belgif.rest.problem.i18n.I18N;
@@ -13,7 +14,7 @@
  *      https://www.belgif.be/specification/rest/api-guide/#bad-gateway</a>
  */
 @ProblemType(BadGatewayProblem.TYPE)
-public class BadGatewayProblem extends ServerProblem {
+public class BadGatewayProblem extends ServerProblem implements FluentProblem<BadGatewayProblem> {
 
     /**
      * The problem type.
diff --git a/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/BadRequestProblem.java b/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/BadRequestProblem.java
index 81dcc9db..35509080 100644
--- a/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/BadRequestProblem.java
+++ b/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/BadRequestProblem.java
@@ -3,6 +3,7 @@
 import java.net.URI;
 import java.util.List;
 
+import io.github.belgif.rest.problem.api.FluentInputValidationProblem;
 import io.github.belgif.rest.problem.api.InputValidationIssue;
 import io.github.belgif.rest.problem.api.InputValidationProblem;
 import io.github.belgif.rest.problem.api.InvalidParam;
@@ -17,7 +18,8 @@
  * @see InputValidationProblem
  */
 @ProblemType(BadRequestProblem.TYPE)
-public class BadRequestProblem extends InputValidationProblem {
+public class BadRequestProblem extends InputValidationProblem
+        implements FluentInputValidationProblem<BadRequestProblem> {
 
     /**
      * The problem type.
diff --git a/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/DefaultProblem.java b/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/DefaultProblem.java
index 8d28eb85..869389ad 100644
--- a/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/DefaultProblem.java
+++ b/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/DefaultProblem.java
@@ -5,6 +5,7 @@
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonProperty;
 
+import io.github.belgif.rest.problem.api.FluentProblem;
 import io.github.belgif.rest.problem.api.Problem;
 import io.github.belgif.rest.problem.api.ProblemType;
 
@@ -16,7 +17,7 @@
  * with the matching problem type URI has been found on the classpath.
  * </p>
  */
-public class DefaultProblem extends Problem {
+public class DefaultProblem extends Problem implements FluentProblem<DefaultProblem> {
 
     private static final long serialVersionUID = 1L;
 
diff --git a/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/ExpiredAccessTokenProblem.java b/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/ExpiredAccessTokenProblem.java
index 8af3d5fb..7b6f985b 100644
--- a/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/ExpiredAccessTokenProblem.java
+++ b/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/ExpiredAccessTokenProblem.java
@@ -6,6 +6,7 @@
 import java.util.Objects;
 
 import io.github.belgif.rest.problem.api.ClientProblem;
+import io.github.belgif.rest.problem.api.FluentProblem;
 import io.github.belgif.rest.problem.api.HttpResponseHeaders;
 import io.github.belgif.rest.problem.api.ProblemType;
 import io.github.belgif.rest.problem.i18n.I18N;
@@ -17,7 +18,8 @@
  *      https://www.belgif.be/specification/rest/api-guide/#expired-access-token</a>
  */
 @ProblemType(ExpiredAccessTokenProblem.TYPE)
-public class ExpiredAccessTokenProblem extends ClientProblem implements HttpResponseHeaders {
+public class ExpiredAccessTokenProblem extends ClientProblem
+        implements FluentProblem<ExpiredAccessTokenProblem>, HttpResponseHeaders {
 
     /**
      * The problem type.
diff --git a/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/InternalServerErrorProblem.java b/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/InternalServerErrorProblem.java
index 229e2f43..240e937f 100644
--- a/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/InternalServerErrorProblem.java
+++ b/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/InternalServerErrorProblem.java
@@ -2,6 +2,7 @@
 
 import java.net.URI;
 
+import io.github.belgif.rest.problem.api.FluentProblem;
 import io.github.belgif.rest.problem.api.ProblemType;
 import io.github.belgif.rest.problem.api.ServerProblem;
 
@@ -13,7 +14,7 @@
  *      https://www.belgif.be/specification/rest/api-guide/#internal-server-error</a>
  */
 @ProblemType(InternalServerErrorProblem.TYPE)
-public class InternalServerErrorProblem extends ServerProblem {
+public class InternalServerErrorProblem extends ServerProblem implements FluentProblem<InternalServerErrorProblem> {
 
     /**
      * The problem type.
diff --git a/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/InvalidAccessTokenProblem.java b/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/InvalidAccessTokenProblem.java
index 622f13a0..7f361d1d 100644
--- a/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/InvalidAccessTokenProblem.java
+++ b/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/InvalidAccessTokenProblem.java
@@ -6,6 +6,7 @@
 import java.util.Objects;
 
 import io.github.belgif.rest.problem.api.ClientProblem;
+import io.github.belgif.rest.problem.api.FluentProblem;
 import io.github.belgif.rest.problem.api.HttpResponseHeaders;
 import io.github.belgif.rest.problem.api.ProblemType;
 import io.github.belgif.rest.problem.i18n.I18N;
@@ -17,7 +18,8 @@
  *      https://www.belgif.be/specification/rest/api-guide/#invalid-access-token</a>
  */
 @ProblemType(InvalidAccessTokenProblem.TYPE)
-public class InvalidAccessTokenProblem extends ClientProblem implements HttpResponseHeaders {
+public class InvalidAccessTokenProblem extends ClientProblem
+        implements FluentProblem<InvalidAccessTokenProblem>, HttpResponseHeaders {
 
     /**
      * The problem type.
diff --git a/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/MissingPermissionProblem.java b/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/MissingPermissionProblem.java
index ad125638..94ad8c95 100644
--- a/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/MissingPermissionProblem.java
+++ b/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/MissingPermissionProblem.java
@@ -2,6 +2,7 @@
 
 import java.net.URI;
 
+import io.github.belgif.rest.problem.api.FluentInputValidationProblem;
 import io.github.belgif.rest.problem.api.InputValidationIssue;
 import io.github.belgif.rest.problem.api.InputValidationProblem;
 import io.github.belgif.rest.problem.api.ProblemType;
@@ -13,7 +14,8 @@
  *      https://www.belgif.be/specification/rest/api-guide/#missing-permission</a>
  */
 @ProblemType(MissingPermissionProblem.TYPE)
-public class MissingPermissionProblem extends InputValidationProblem {
+public class MissingPermissionProblem extends InputValidationProblem
+        implements FluentInputValidationProblem<MissingPermissionProblem> {
 
     /**
      * The problem type.
diff --git a/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/MissingScopeProblem.java b/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/MissingScopeProblem.java
index 664bea14..864a810e 100644
--- a/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/MissingScopeProblem.java
+++ b/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/MissingScopeProblem.java
@@ -11,6 +11,7 @@
 import com.fasterxml.jackson.annotation.JsonSetter;
 
 import io.github.belgif.rest.problem.api.ClientProblem;
+import io.github.belgif.rest.problem.api.FluentProblem;
 import io.github.belgif.rest.problem.api.HttpResponseHeaders;
 import io.github.belgif.rest.problem.api.ProblemType;
 
@@ -21,7 +22,8 @@
  *      https://www.belgif.be/specification/rest/api-guide/#missing-scope</a>
  */
 @ProblemType(MissingScopeProblem.TYPE)
-public class MissingScopeProblem extends ClientProblem implements HttpResponseHeaders {
+public class MissingScopeProblem extends ClientProblem
+        implements FluentProblem<MissingScopeProblem>, HttpResponseHeaders {
 
     /**
      * The problem type.
diff --git a/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/NoAccessTokenProblem.java b/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/NoAccessTokenProblem.java
index 9eea4c63..8bc22cf1 100644
--- a/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/NoAccessTokenProblem.java
+++ b/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/NoAccessTokenProblem.java
@@ -6,6 +6,7 @@
 import java.util.Objects;
 
 import io.github.belgif.rest.problem.api.ClientProblem;
+import io.github.belgif.rest.problem.api.FluentProblem;
 import io.github.belgif.rest.problem.api.HttpResponseHeaders;
 import io.github.belgif.rest.problem.api.ProblemType;
 import io.github.belgif.rest.problem.i18n.I18N;
@@ -17,7 +18,8 @@
  *      https://www.belgif.be/specification/rest/api-guide/#no-access-token</a>
  */
 @ProblemType(NoAccessTokenProblem.TYPE)
-public class NoAccessTokenProblem extends ClientProblem implements HttpResponseHeaders {
+public class NoAccessTokenProblem extends ClientProblem
+        implements FluentProblem<NoAccessTokenProblem>, HttpResponseHeaders {
 
     /**
      * The problem type.
diff --git a/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/PayloadTooLargeProblem.java b/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/PayloadTooLargeProblem.java
index 16b55188..e0ef0c9e 100644
--- a/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/PayloadTooLargeProblem.java
+++ b/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/PayloadTooLargeProblem.java
@@ -4,6 +4,7 @@
 import java.util.Objects;
 
 import io.github.belgif.rest.problem.api.ClientProblem;
+import io.github.belgif.rest.problem.api.FluentProblem;
 import io.github.belgif.rest.problem.api.ProblemType;
 
 /**
@@ -13,7 +14,7 @@
  *      https://www.belgif.be/specification/rest/api-guide/#payloadTooLargeProblem</a>
  */
 @ProblemType(PayloadTooLargeProblem.TYPE)
-public class PayloadTooLargeProblem extends ClientProblem {
+public class PayloadTooLargeProblem extends ClientProblem implements FluentProblem<PayloadTooLargeProblem> {
 
     /**
      * The problem type.
diff --git a/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/ResourceNotFoundProblem.java b/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/ResourceNotFoundProblem.java
index 090a6b29..9e17acaa 100644
--- a/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/ResourceNotFoundProblem.java
+++ b/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/ResourceNotFoundProblem.java
@@ -2,6 +2,7 @@
 
 import java.net.URI;
 
+import io.github.belgif.rest.problem.api.FluentInputValidationProblem;
 import io.github.belgif.rest.problem.api.InEnum;
 import io.github.belgif.rest.problem.api.InputValidationIssue;
 import io.github.belgif.rest.problem.api.InputValidationProblem;
@@ -17,7 +18,8 @@
  * @see InputValidationProblem
  */
 @ProblemType(ResourceNotFoundProblem.TYPE)
-public class ResourceNotFoundProblem extends InputValidationProblem {
+public class ResourceNotFoundProblem extends InputValidationProblem
+        implements FluentInputValidationProblem<ResourceNotFoundProblem> {
 
     /**
      * The problem type.
diff --git a/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/ServiceUnavailableProblem.java b/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/ServiceUnavailableProblem.java
index f33dcbfd..d18bbf2b 100644
--- a/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/ServiceUnavailableProblem.java
+++ b/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/ServiceUnavailableProblem.java
@@ -2,6 +2,7 @@
 
 import java.net.URI;
 
+import io.github.belgif.rest.problem.api.FluentRetryAfterProblem;
 import io.github.belgif.rest.problem.api.ProblemType;
 import io.github.belgif.rest.problem.api.RetryAfterServerProblem;
 
@@ -12,7 +13,8 @@
  *      https://www.belgif.be/specification/rest/api-guide/#service-unavailable</a>
  */
 @ProblemType(ServiceUnavailableProblem.TYPE)
-public class ServiceUnavailableProblem extends RetryAfterServerProblem {
+public class ServiceUnavailableProblem extends RetryAfterServerProblem
+        implements FluentRetryAfterProblem<ServiceUnavailableProblem> {
 
     /**
      * The problem type.
diff --git a/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/TooManyFailedRequestsProblem.java b/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/TooManyFailedRequestsProblem.java
index 751374db..8d0b870c 100644
--- a/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/TooManyFailedRequestsProblem.java
+++ b/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/TooManyFailedRequestsProblem.java
@@ -3,6 +3,7 @@
 import java.net.URI;
 import java.util.Objects;
 
+import io.github.belgif.rest.problem.api.FluentRetryAfterProblem;
 import io.github.belgif.rest.problem.api.ProblemType;
 import io.github.belgif.rest.problem.api.RetryAfterClientProblem;
 
@@ -14,7 +15,8 @@
  *      https://www.belgif.be/specification/rest/api-guide/#too-many-failed-requests</a>
  */
 @ProblemType(TooManyFailedRequestsProblem.TYPE)
-public class TooManyFailedRequestsProblem extends RetryAfterClientProblem {
+public class TooManyFailedRequestsProblem extends RetryAfterClientProblem
+        implements FluentRetryAfterProblem<TooManyFailedRequestsProblem> {
 
     /**
      * The problem type.
diff --git a/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/TooManyRequestsProblem.java b/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/TooManyRequestsProblem.java
index 19c9f803..91e7cf9d 100644
--- a/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/TooManyRequestsProblem.java
+++ b/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/TooManyRequestsProblem.java
@@ -3,6 +3,7 @@
 import java.net.URI;
 import java.util.Objects;
 
+import io.github.belgif.rest.problem.api.FluentRetryAfterProblem;
 import io.github.belgif.rest.problem.api.ProblemType;
 import io.github.belgif.rest.problem.api.RetryAfterClientProblem;
 
@@ -13,7 +14,8 @@
  *      https://www.belgif.be/specification/rest/api-guide/#too-many-requests</a>
  */
 @ProblemType(TooManyRequestsProblem.TYPE)
-public class TooManyRequestsProblem extends RetryAfterClientProblem {
+public class TooManyRequestsProblem extends RetryAfterClientProblem
+        implements FluentRetryAfterProblem<TooManyRequestsProblem> {
 
     /**
      * The problem type.
diff --git a/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/api/FluentInputValidationProblem.java b/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/api/FluentInputValidationProblem.java
new file mode 100644
index 00000000..c3b84012
--- /dev/null
+++ b/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/api/FluentInputValidationProblem.java
@@ -0,0 +1,28 @@
+package io.github.belgif.rest.problem.api;
+
+import java.util.List;
+
+/**
+ * Provides default methods with fluent InputValidationProblem properties (issues).
+ *
+ * @param <SELF> the concrete InputValidationProblem self-type
+ */
+@SuppressWarnings("unchecked")
+public interface FluentInputValidationProblem<SELF extends InputValidationProblem & FluentInputValidationProblem<SELF>>
+        extends FluentProblem<SELF> {
+
+    void setIssues(InputValidationIssue... issues);
+
+    void setIssues(List<InputValidationIssue> issues);
+
+    default SELF issues(InputValidationIssue... issues) {
+        setIssues(issues);
+        return (SELF) this;
+    }
+
+    default SELF issues(List<InputValidationIssue> issues) {
+        setIssues(issues);
+        return (SELF) this;
+    }
+
+}
diff --git a/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/api/FluentProblem.java b/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/api/FluentProblem.java
new file mode 100644
index 00000000..1cf40516
--- /dev/null
+++ b/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/api/FluentProblem.java
@@ -0,0 +1,41 @@
+package io.github.belgif.rest.problem.api;
+
+import java.net.URI;
+
+/**
+ * Provides default methods with fluent Problem properties (detail, href, instance, additionalProperty).
+ *
+ * @param <SELF> the concrete Problem self-type
+ */
+@SuppressWarnings("unchecked")
+public interface FluentProblem<SELF extends Problem & FluentProblem<SELF>> {
+
+    void setDetail(String detail);
+
+    void setHref(URI href);
+
+    void setInstance(URI instance);
+
+    void setAdditionalProperty(String name, Object value);
+
+    default SELF detail(String detail) {
+        setDetail(detail);
+        return (SELF) this;
+    }
+
+    default SELF href(URI href) {
+        setHref(href);
+        return (SELF) this;
+    }
+
+    default SELF instance(URI instance) {
+        setInstance(instance);
+        return (SELF) this;
+    }
+
+    default SELF additionalProperty(String name, Object value) {
+        setAdditionalProperty(name, value);
+        return (SELF) this;
+    }
+
+}
diff --git a/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/api/FluentRetryAfterProblem.java b/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/api/FluentRetryAfterProblem.java
new file mode 100644
index 00000000..f097763e
--- /dev/null
+++ b/belgif-rest-problem/src/main/java/io/github/belgif/rest/problem/api/FluentRetryAfterProblem.java
@@ -0,0 +1,28 @@
+package io.github.belgif.rest.problem.api;
+
+import java.time.OffsetDateTime;
+
+/**
+ * Provides default methods with fluent RetryAfter problem properties (retryAfter, retryAfterSec).
+ *
+ * @param <SELF> the concrete RetryAfter Problem self-type
+ */
+@SuppressWarnings("unchecked")
+public interface FluentRetryAfterProblem<SELF extends Problem & RetryAfter & FluentRetryAfterProblem<SELF>>
+        extends FluentProblem<SELF> {
+
+    void setRetryAfter(OffsetDateTime retryAfter);
+
+    void setRetryAfterSec(Long retryAfterSec);
+
+    default SELF retryAfter(OffsetDateTime retryAfter) {
+        setRetryAfter(retryAfter);
+        return (SELF) this;
+    }
+
+    default SELF retryAfterSec(Long retryAfterSec) {
+        setRetryAfterSec(retryAfterSec);
+        return (SELF) this;
+    }
+
+}
diff --git a/belgif-rest-problem/src/test/java/adoc/CodeSamples.java b/belgif-rest-problem/src/test/java/adoc/CodeSamples.java
index 43ee5231..248d5397 100644
--- a/belgif-rest-problem/src/test/java/adoc/CodeSamples.java
+++ b/belgif-rest-problem/src/test/java/adoc/CodeSamples.java
@@ -6,6 +6,7 @@
 import io.github.belgif.rest.problem.BadRequestProblem;
 import io.github.belgif.rest.problem.ResourceNotFoundProblem;
 import io.github.belgif.rest.problem.api.ClientProblem;
+import io.github.belgif.rest.problem.api.FluentProblem;
 import io.github.belgif.rest.problem.api.InEnum;
 import io.github.belgif.rest.problem.api.InputValidationIssue;
 import io.github.belgif.rest.problem.api.Problem;
@@ -15,7 +16,8 @@ public class CodeSamples {
 
     // tag::api-local-problem[]
     @ProblemType(TooManyResultsProblem.TYPE)
-    public static class TooManyResultsProblem extends ClientProblem {
+    public static class TooManyResultsProblem extends ClientProblem
+            implements FluentProblem<TooManyResultsProblem> {
 
         public static final String TYPE = "urn:problem-type:cbss:legallog:tooManyResults";
         public static final URI TYPE_URI = URI.create(TYPE);
diff --git a/belgif-rest-problem/src/test/java/io/github/belgif/rest/problem/BadRequestProblemTest.java b/belgif-rest-problem/src/test/java/io/github/belgif/rest/problem/BadRequestProblemTest.java
index a85a20b2..c367ccd3 100644
--- a/belgif-rest-problem/src/test/java/io/github/belgif/rest/problem/BadRequestProblemTest.java
+++ b/belgif-rest-problem/src/test/java/io/github/belgif/rest/problem/BadRequestProblemTest.java
@@ -2,12 +2,14 @@
 
 import static org.assertj.core.api.Assertions.*;
 
+import java.net.URI;
 import java.util.Collections;
 
 import org.junit.jupiter.api.Test;
 
 import io.github.belgif.rest.problem.api.InEnum;
 import io.github.belgif.rest.problem.api.InputValidationIssue;
+import io.github.belgif.rest.problem.api.InputValidationIssues;
 import io.github.belgif.rest.problem.api.InvalidParam;
 import io.github.belgif.rest.problem.api.ProblemType;
 
@@ -72,6 +74,21 @@ void problemTypeAnnotation() {
                 .isEqualTo("urn:problem-type:belgif:badRequest");
     }
 
+    @Test
+    void fluentProperties() {
+        BadRequestProblem problem = new BadRequestProblem()
+                .detail("detail")
+                .issues(InputValidationIssues.requiredInput(InEnum.QUERY, "test"))
+                .href(URI.create("href"))
+                .instance(URI.create("instance"))
+                .additionalProperty("foo", "bar");
+        assertThat(problem.getDetail()).isEqualTo("detail");
+        assertThat(problem.getHref()).hasToString("href");
+        assertThat(problem.getInstance()).hasToString("instance");
+        assertThat(problem.getAdditionalProperties()).containsEntry("foo", "bar");
+        assertThat(problem.getIssues()).containsExactly(InputValidationIssues.requiredInput(InEnum.QUERY, "test"));
+    }
+
     @Test
     void equalsAndHashCode() {
         InputValidationIssue issue = new InputValidationIssue(InEnum.QUERY, "test");
diff --git a/src/main/asciidoc/index.adoc b/src/main/asciidoc/index.adoc
index f6dacf4e..c1addb30 100644
--- a/src/main/asciidoc/index.adoc
+++ b/src/main/asciidoc/index.adoc
@@ -353,6 +353,7 @@ The https://www.belgif.be/specification/rest/api-guide/#rule-prb-type[naming con
 include::../../../belgif-rest-problem/src/test/java/adoc/CodeSamples.java[tag=api-local-problem]
 ----
 
+If you want fluent setter properties in your custom problem type, you can implement the `FluentProblem` interface.
 Your custom problem type can define additional properties if necessary.
 For problem types related to input parameters, you can extend from `InputValidationProblem` instead of `Problem`.
 
diff --git a/src/main/asciidoc/release-notes.adoc b/src/main/asciidoc/release-notes.adoc
index e822c662..88571935 100644
--- a/src/main/asciidoc/release-notes.adoc
+++ b/src/main/asciidoc/release-notes.adoc
@@ -20,6 +20,10 @@
 * Don't include null (issue) input values when serializing
 * Replace `urn:problem-type:cbss:input-validation:referencedResourceNotFound`
 by standardized `urn:problem-type:belgif:input-validation:referencedResourceNotFound`
+* Add fluent setter methods:
+** Problem: detail, href, instance, additionalProperties
+** InputValidationProblem: issues
+** RetryAfterProblem: retryAfter, retryAfterSec
 * Improve WWW-Authenticate header for token-related problem types:
 ** Support setting the "realm" attribute
 ** Add "error_description" and "scope" attributes for missing_scope